Slack take-up device



Oct. 7, 1941. R. l.. MULLANEY sLAcK TAKE-UP DEVICE Filed May 6, 1940 ATT RNEYJ` VBY Patented Oct. 7, 1941 UNITEDz STATES PATENT OFFICE y sLAcK TAKE-Ur DEVICE nicharar.. Mullaney, West Hartford, conn., lail-f signor to The Whitney Chain `t Mfg. Company, Hartford, Conn., a corporation of Connecticut 1,'

Application May 6, 1940, serial No. 333,477 4 claims. (c1. #i4-242.11) This invention relates to a novel and improved Fig. `3 is a section approximately on the line 3-3 of Fig. 2;

Fig. 4 is a View rapproximately on the line 4-4 of Fig. 2, but showing the shaft turned from the position which it occupies in Fig. 1;

Fig. 5 is a View showing the shaft, bearing, and pinion detached from the other parts. l

Referring rst Vto Fig., 1, I have shown therein a chain drive, such for example as is used in the operation of timing mechanism in an automobile. 'I'he invention finds particular utility in such drives and, for the sake of convenience, I shall assume that it is a chain in which the slack is to be taken up by the device, although it will be understood that the device may be used with a belt or other drive wherever found desirable.

In Fig. 1, the chain I is shown as engaging sprockets on three shafts 2, 3, and 4, and the take-up device is shown as having a sprocket or other idler 5 engaging in a bight or loop 6 of the chain. Of course, where a belt is used, the sprocket will be replaced by a roller adapted to engage a belt.

The take-up device comprises a body 'I which may be secured by bolts or otherwise to any fixed part 8 of the machine with which the device is used. That body is shown as provided with a bore 9 in which is rotatably mounted a shaft I supported on suitable bearings, here shown as a bushing II.

The front end of the shaft, by which is meant the end which projects from the body, is provided with an arm I2 which extends transversely of the shaft and which is in the nature of a crank arm. On the arm I2 and parallel to but olf-set from the shaft III is a bearing I3, which is preferably integral with the arm I2 and shaft I0. This bearing is shown as being cylindrical, but may be conical or any other suitable form, a cylindrical bearing being selected merely for purpose of illustration. Not only is the bearing eccentric to the shaft I0, but is bodily offset therefrom.

The sprocket is mounted on the bearing I3 and is freely rotatable thereon. For example, anti-friction bearings I4 may be used between the bearing I3 and the sprocket if desired, so as to give a free rotation to the sprocket.

Secured to the shaft I Il, asby a 'pin I5, is a pinion I6 which engages with a rack l1 which is slidable in a chamber I8 of the body 7. This chamber, as is best shown in Figs. 2 and 4, extends from end to end of the body at approximately right angles to the shaft I0, and its opposite ends are open and provided with duplicate seats I9 and 20. i

Extending lengthwise through the chamber I8 is a rod 2| which is secured at one end to a closure 22 which is adapted to seat against either the seat I9 or the seat 20 so as to close the chamber. At its other end the rod is threaded, as indicated in Figs. 2 and 4, and over that threaded end is slid or, if desired, is threaded a second closure 23 which likewise is adapted to seat against either the seat I9 or the seat 20. Preferably, I merely slide the closure 23 over the threaded end of the rod and then secure it in place by means of the nut 24 which will draw the two closures together to force them against their respective seats.

The rod 2|, as shown, passes through the body of the rack I1, and disposed in a bore 25 within that body is a spring 26 which bears against an abutment 21 on the rack and against a nut 28 which is threaded on the rod 2| so that the force of the spring may be adjusted.

In operation, the device is placed in such position with relation to the bight of the chain that the sprocket will engage the chain in that bight. The spring is charged, in this instance being placed under compression, and the device is so placed that the spring tends to rotate the shaft and thus force the sprocket 5 into the bight of the chain and keep the chain tight. As the chain wears or the size of the bight increases for any reason, the slack is automatically taken up by the action of the spring.l For example, assuming that the device, as it is shown in Fig. 2 is placed within the bight, then it will be seen that as slack occurs, the shaft will be rotated in a counterclockwise direction (as shown by arrows in Figs.

1 and 4) and cause the slack to be taken up. In Fig. 4, the parts are shown where a quarter revolution of the shaft has taken place, which will bring the sprocket upwardly (in Figs. 1 and 2) and thus take up any slack which has occurred in the chain.

yIf it is desired to reverse the direction of rotation of the shaft, then the nut 24 may be removed which will permit sliding of the entire rack and rod out of the chamber I8 and then it may be bearing for the sprocket, and in fact a smallersproicket or idler is thus made possible. At the same time, the slack will be controlled by the rack and pinion as in said Do'vf patent, but the rack is embodied in a unitwhich can be 'more readily removed and reversedA ywhen desired. Other advantages will suggest themselvesv to those skilled in the art.

While I have shown the invention as embodied -ina speci-o form, itis to be understood that Various changes in detailsmay loel made Without departing from the scope of thev invention as -dened by the appended claims.

' Il. claim: a

1. Ina slack take-,up device,. aA rotatable shaft, an; arml on one end` ofsaidf shaft and extending transversely thereof, a bearing rigid with said armand parallelv to said kshaft but offset therefrom, an idler freely rotatable on said bearing i on the center lien of said idlery a pinion secured tof said shaft, a slid-able rack engaging said pinion,jand a spring uitging said rack in one direc- 1tionto rotate` said shaft in one direction.

v2.A In a. slack take-up device having al rotatable shaft andi an idler eccentrically supported thereorna pinion secured to said shaft, a rack engaging. said pinion and disposed in an elongated chamber having its; two opposite ends open and provided With closure seats, a rod extending' through said chamber, a nut threaded on said rod, an abutment on said rack, a spring acting between said nut and abutment to move said rack, a closure for one end of the chamber and fixed to one end of the rod, a second closure for the other end of the chamber and slidable over the other endof the rod, and a nut threaded on said last-named end, to clamp both closures against said seats.

3. In a slack take-up device having a rotatable 'shaft and an idler eccentrically supported thereon, a pinion secured to said shaft, a rack engaging said pinion and disposed in an elongated chamber having its two opposite ends open and provided with closure seats, a rod extending through said chamber, a nut threaded on said rod, an abutment on said rack, a spring acting between` said nut and abutment to move said rack, a closure for one end of the chamber and fixed ito one' en'd of thel rod, a second closure for the othei` end of -the chamber and slidable over vthe other end oi the rod, and a nut threaded on said last-named end, to clampy both closures against saidi seats, said closures and seats being respectively duplicates of' each other.

4. In a slack` takeup device, a rotatable shaft, an arm on one end oi said shaft and extending transversely thereof, a bearing rigid with said arm. and parallel to said shaft but offset therefrom', an idler' freely rotatable on said bearing on the center line of said idler, a pinion Secured to said. shaft, a slidable rack engaging said pinion, and. a coinpr'ession spring urging said rack in a direction to rotate said shaft in that direction tending to give said idler the maximum take-up effect.

RICHARD L, MULLANEY. 

